I have had some wonderful results from wills. My great x6 grandfather James Garnham is a case in point. I had traced back to my great x4 grandfather Ambrose Frost, I had his baptism so I knew his mother's name was Sarah. A distant relative who posts here gave me her maiden name as Garnham, and various other details which I was having difficulty verifying for myself. But a random internet search for "Ambrose Frost" took me to a now-defunct site with what purported to be a transcript of the will of James Garnham, the maternal grandfather of Ambrose Frost. I went to Bury St Edmunds to see the will for myself - and the bequest was everything a family historian could ever hope for!! "I also give to my grandson Ambrose Frost the son of my daughter Sarah the wife of William Frost the sum of five pounds to be paid to him on his attaining the age of twenty one years".
You can't get a much clearer statement of the family relationship than that!!
I have quite a few ancestors who were licensed victuallers, and I have found the annual justices' recognisances a valuable source of information as to when they moved from one public house to another.
The register of apprenticeships has given me a couple of useful leads, too.
I've found evidence of a number of bankruptcies amongst my Victiorian ancestors in the London Gazette. This is now fully digitized and will show up in the results of a search against the name of your bankrupt ancestor. Not much use if it's John Smith that you're looking for; but Edward Martindale is another matter ... and the fact of the bankruptcy helps to explain all sorts of things. Sudden disappearance from one location only to reappear in another, using a different name, for example.
The Old Bailey records are also online, and make for very interesting reading. Transcripts of every trial, including the evidence given, is there and searchable. Witnesses' names, addresses and occupations are all faithfully recorded. I had an ancestor with a distinctive name (Robert Packman) who was a City of London policeman in the Victorian era. A search against his name yielded a directory of the 60 odd trials in which he gave evidence; from which a very clear picture of his career emerges.
As the National Newspaper Library is digitizing its collection, it is worth doing random internet searches against the names of your more obscure ancestors from time to time. Interesting reports come up. Now I know just why the family had photographs of my great great grandmother Emma Hardwick, but knew absolutely nothing about her husband (judicial separation in 1907; luridly reported in the local newspaper of the time, along with the sorry tale of his subsequent conviction for breaking into my great grandfather's house, where she was living after the separation, and stealing her money and smashing her sewing machine).
The Great Fire of Potton in 1783 has left us with a quasi-census of the town, in the form of the accounts of the trustees of the relief fund which can be consulted at the Bedfordshire and Luton Archives and Records Service. It lists all the claimants, the amount of their loss, whether or not their claim was accepted and in which class, and the amount of the relief paid to them (16s. in the £ in the case of Class 1 claimants, which is pretty good relief).
Still searching, still finding interesting little odds and sods all over the place ...